• Journal of the Computational Structural Engineering Institute of Korea
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• v.37 no.1
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• pp.67-76
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• 2024

In this paper, we present a DIP-MLS testing method that combines digital image processing with a rigid body-based MLS differencing approach to measure mechanical variables and analyze the impact of target location and image resolution. This method assesses the displacement of the target attached to the sample through digital image processing and allocates this displacement to the node displacement of the MLS differencing method, which solely employs nodes to calculate mechanical variables such as stress and strain of the studied object. We propose an effective method to measure the displacement of the target's center of gravity using digital image processing. The calculation of mechanical variables through the MLS differencing method, incorporating image-based target displacement, facilitates easy computation of mechanical variables at arbitrary positions without constraints from meshes or grids. This is achieved by acquiring the accurate displacement history of the test specimen and utilizing the displacement of tracking points with low rigidity. The developed testing method was validated by comparing the measurement results of the sensor with those of the DIP-MLS testing method in a three-point bending test of a rubber beam. Additionally, numerical analysis results simulated only by the MLS differencing method were compared, confirming that the developed method accurately reproduces the actual test and shows good agreement with numerical analysis results before significant deformation. Furthermore, we analyzed the effects of boundary points by applying 46 tracking points, including corner points, to the DIP-MLS testing method. This was compared with using only the internal points of the target, determining the optimal image resolution for this testing method. Through this, we demonstrated that the developed method efficiently addresses the limitations of direct experiments or existing mesh-based simulations. It also suggests that digitalization of the experimental-simulation process is achievable to a considerable extent.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.29 no.1
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• pp.28-41
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• 2024

The carbon balance serves as a valuable indicator of a plant's physiological status under diverse environmental conditions. We investigated the photosynthetic and respiratory responses of the Asian surfgrass Phyllospadix iwatensis along the northeast coast of the Korean peninsula in response to changing water temperature (ranging from 5℃ to 30℃) to estimate the seasonal whole-plant carbon balance through a series of incubation experiments. The maximum gross photosynthetic rate (P_max) showed a significant difference among the temperature treatments, while there was no significant difference in photosynthetic efficiency (α). The maximum gross photosynthetic rate of P. iwatensis reached its peaks at 20℃ treatment (101.65 μmol O₂ g^-1 DW h^-1) but decreased rapidly at 30℃. The saturation irradiance (I_k), compensation irradiance (I_c), and respiration rate (R) of P. iwatensis exhibited significant differences among the temperature treatments. The saturation irradiance increased up to 20-25℃ (121.59-124.50 μmol photons m^-2 s^-1) and sharply decreased at 30℃. The compensation irradiance and respiration rate increased steadily with rising water temperature. The ratio of P_max to R (P_max:R ratio) was the highest at 5℃ but dramatically decreased at 30℃. The whole-plant carbon balance, calculated based on photosynthetic parameters, respiration rates, and biomass, exhibited distinct seasonal variation, increasing during winter and spring and decreasing during summer and fall, which is consistent with the highest in situ growth in spring and severely limited growth at the highest water temperature conditions. Phyllospadix iwatensis displayed a negative carbon balance during late summer, fall, and winter, but demonstrated a positive carbon balance during spring and early summer. Our findings suggest that the rising seawater temperatures associated with climate change may lead to significant alterations in the seagrass ecosystem functioning along the rocky shores of the Korean east coast.

• Journal of Life Science
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• v.34 no.5
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• pp.339-355
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• 2024

The pulmonary system is a highly complex system that can only be understood by integrating its functional and structural aspects. Hence, in vivo animal models are generally used for pathological studies of pulmonary diseases and the evaluation of inhalation toxicity. However, to reduce the number of animals used in experimentation and with the consideration of animal welfare, alternative methods have been extensively developed. Notably, the Organization for Economic Co-operation and Development (OECD) and the United States Environmental Protection Agency (USEPA) have agreed to prohibit animal testing after 2030. Therefore, the latest advances in biotechnology are revolutionizing the approach to developing in vitro inhalation models. For example, lung organ-on-a-chip (OoC) and organoid models have been intensively studied alongside advancements in three-dimensional (3D) bioprinting and microfluidic systems. These modeling systems can more precisely imitate the complex biological environment compared to traditional in vivo animal experiments. This review paper addresses multiple aspects of the recent in vitro modeling systems of lung OoC and organoids. It includes discussions on the use of endothelial cells, epithelial cells, and fibroblasts composed of lung alveoli generated from pluripotent stem cells or cancer cells. Moreover, it covers lung air-liquid interface (ALI) systems, transwell membrane materials, and in silico models using artificial intelligence (AI) for the establishment and evaluation of in vitro pulmonary systems.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.50 no.2
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• pp.179-192
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• 2024

In this study, six types of natural products, Prunus tomentosa (P. tomentosa), Akebia quinata (A. quinata), Prunus armeniaca (P. armeniaca), Smallanthus sonchifolius (S. sonchifolius), Citrus japonica (C. japonica), and Citrus australasica (C. australasica), were used to verify the effect of improving sleep and skin barriers by stress relief. As a result of the experiment, the production of cortisol, a stress hormone, was significantly inhibited by the P. tomentosa, C. australasica, A. quinata, and C. japonica among the six natural products. In addition, the expression of GAD67, a GABA-producing enzyme involved in sleep regulation, showed a significant increase in P. tomentosa purified water extract and C. australasica 50% ethanol extract, and the extract by each P. tomentosa solvent was found to have the highest total polyphenol content. Based on the results, the P. tomentosa extract with the highest activity was finally selected, and subsequent experiments were conducted. Among each P. tomentosa solvent extract, the DPPH radical scavenging activity was the highest in the 30% ethanol extract, and purified water extract increased GABA production and skin barrier factors filaggrin and claudin-1 expression the highest. HPLC analysis confirmed quercitrin as the main component of P. tomentosa extract, and quercitrin content by extraction solvent was high in the order of 30% ethanol > purified water > 70% ethanol > 50% ethanol. Quercitrin inhibited the production of cortisol in a concentration-dependent manner, significantly increasing GAD67 expression and GABA production, which had been reduced by cortisol. From the results of this study, it has been demonstrated that P. tomentosa can be used as a cosmetic material to help improve sleep and strengthen skin barriers by relieving stress.

• Korean Journal of Cognitive Science
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• v.35 no.2
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• pp.129-159
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• 2024

In the process of reading, readers can process information not only within the fixated region, known as the fovea, but also in the parafoveal region to the right of the fovea. While the parafoveal semantic preview effect has been confirmed in eye-tracking experiments using boundary techniques, research on how the parafoveal preview effects differ depending on the degree of semantic relatedness is still limited. This study investigates the parafoveal preview effects as a function of semantic relatedness with the target word. The experiment utilized Korean-Chinese bilinguals and presented mixed-language sentences as experimental stimuli. Four parafoveal preview conditions were applied to the target words in each sentence: (1) Korean identical condition, where the parafoveal word was the same as the target word (e.g., "나라," meaning "country" in English), (2) Chinese synonymous condition, where the parafoveal word had the same meaning as the target word (e.g., "国家," also meaning "country" in English), (3) Chinese semantically related condition, where the parafoveal word was semantically related to the target word (e.g., "政权," meaning "political power" in English), and (4) Chinese unrelated condition, where the parafoveal word was semantically unrelated to the target word (e.g., "围裙," meaning "apron" in English). The study explored the parafoveal preview effect in terms of the degree of semantic association with the target word. We found the most pronounced preview effect in conditions where the preview and the target word shared the same meaning, and we also observed preview effects in conditions where the semantic relatedness with the target word was relatively weak. This study suggests that the degree of semantic relatedness between the parafoveal preview word and the target word can influence readers' reading processes. It contributes to a better understanding of readers' eye movements and comprehension processes, with potential implications for the development of effective reading strategies and educational methods.

• Food Science and Preservation
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• v.30 no.6
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• pp.1082-1094
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• 2023

The purpose of this study was to examine the characteristics of Leuconostoc spp. isolated from radish kimchi and to investigate the potential for the use of functional ingredients by evaluating enzymatic characteristics, safety, and immune-enhancing effects among the isolates, including Lactobacillus rhamnosus ATCC53103 (LGG) as a control strain. All test strains exhibited β-glucosidase enzyme activity that releases β-1,4 sugar chain bonds. In addition, as a result of antibiotic resistance assay among the isolates, MIC values on 8 antibiotics were below compared to the EFSA standard, and hemolytic experiments confirmed that all showed gamma hemolysis without hemolytic ability. As a result of the antibacterial activity experiment, the Leu. mesenteroides K2-4 strain showed a higher activity than LGG against Bacillus cereus and Staphylococcus aureus. Additionally, the activity of the NF-kB/AP-1 transcription factor increased when the isolates were treated in macrophage RAW cells. These results were related to increasing the high mRNA expression levels on TNF-α and IL-6 by Leu. mesenteroides K2-4 strain to be treated at low concentration. Consequently, we suggest that it will be useful as a candidate for functional food ingredients.

• Journal of Practical Agriculture & Fisheries Research
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• v.25 no.4
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• pp.24-38
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• 2024

Five species of plants (Pimpinella brachycarpa (Kom.) Nakai, Hylotelephium erythrostictum (Miq.) H. Ohba, Magnolia sieboldii K. Koch, Sanguisorba hakusanensis Makino, Agastache rugosa (Fisch. & Mey.) Kuntze) native to the clean area of Mt. Jiri were selected. The collection period was from May to September 2021, and the five species plants were collected in their native habitats with flowers in full bloom. The collected plants were extracted with 70% EtOH and 17 kinds of polyphenol components were analyzed. Next, flowers, leaves and roots were separated from plants, extracted with 70% EtOH for each part and experiments were conducted on DPPH, ABTS, total polyphenols, and total flavonoids. The results are as follows. 1. There were a total of 13 polyphenol components contained in the 5 species of plants native to Mt. Jiri. Among them, the total content of the most detected substance was Sanguisorba hakusanensis Makino, which was 126.2 ppm, and the main substance was ellagic acid (=ELA), which was 122.4 ppm. 2. As a result of examining the DPPH radical scavenging activity, the flowers, stems, and roots of Sanguisorba hakusanensis Makino showed the best scavenging activity, while the flower extracts of other plants showed good scavenging activity. 3. The highest ABTS radical scavenging activity was Sanguisorba hakusanensis Makino flower extract at 13.5 ㎍/㎖, followed by roots at 16.8 ㎍/㎖ and leaves at 22.6 ㎍/㎖;. Although such a large ABTS radical scavenging activity could not be confirmed in other plants, the flower extract was overall better than the leaf and root extracts of other parts. 4. The highest total polyphenol content was found in the leaves of Magnolia sieboldii K. Koch, at 161.4mg GAE/g, followed by the highest content in the roots of Magnolia sieboldii K. Koch and the roots of Agastache rugosa (Fisch. & Mey.) Kuntze, at 130.0mg GAE/g. Also, the lowest was found to be Sanguisorba hakusanensis Makino. 5. The total flavonoid content was 186.2mg CAE/g in the roots of Agastache rugosa (Fisch. & Mey.) Kuntze, 166.9mg CAE/g in the flowers, and the lowest was 116.1mg CAE/g in the leaves. As shown in the results above, Sanguisorba hakusanensis Makino has excellent antioxidant efficacy and has a high polyphenol content, so it is expected to be fully utilized in the cosmetics industry in the future.

• Journal of Science Education
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• v.47 no.3
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• pp.238-250
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• 2023

This study aims to explore the effect of an appropriate technology program related to water acquisition and purification on scientific attitudes and creative problem-solving skills in elementary school students. Thus, this study developed a learning program related to the appropriate technology composed of 8 sessions, and some were for exploring water acquisition-related scientific principles and the appropriated technology of Warka Tower, and the others were for conducting water purification-related inquiry experiments, such as Life Straw and Drinkable Book, and the last two sessions were for presenting practical tasks through creative ideas and designs and carrying out the relevant campaign activities. For research subjects, this study selected 51 students from two sixth-grade classes, and after modifying the scientific attitude questionnaire and the creative problem-solving skill questionnaire fit for the environment and situation, this study conducted a paired-sample t-test by applying both the questionnaires before and after this program. In addition, while looking into the correlation between scientific attitudes and creative problem-solving skills, based on the post-test results, this study examined relationships between sub-domains perceived by the students after this program was applied. The results can be summarized as below. Out of all the scientific attitudes, curiosity, openness, cooperation, and creativity showed statistically significant results with an increase in the average value when their overall averages of the pre-test were compared with those of the post-test. With creative problem-solving skills, the domain of mastering a specific area and the domain of divergent thinking showed statistically significant results. The correlation analysis results showed that cooperation out of the scientific attitudes had a significant correlation with all the domains of creative problem-solving skills, especially showing the highest correlation coefficient with such sub-domains as critical and logical thinking. All the four domains of creative problem-solving skills showed a number of significant correlations with the sub-domains of scientific attitudes. Through the research results above, this study has several implications on how and where to apply such appropriate technology-related topics in the future and various responses from students.

• Food Science and Preservation
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• v.31 no.2
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• pp.315-323
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• 2024

This study aims to confirm the anti-inflammatory activities of acemannan and aloesin, which have been studied for various efficacies at various mixed sample ratios. The mixed samples were mixed at a ratio of 1:1 (AA-1), 1:2 (AA-2), 1:3 (AA-3), 2:1 (AA-4), and 3:1 (AA-5). Seven samples were evaluated for their cytotoxic ability on macrophages, and the results showed that all cell viability was over 90% at a concentration of 100 ㎍/mL. First, due to the NO production inhibitory activity, a better inhibitory effect was achieved when using a mixed sample rather than a single material. Afterward, the activity of inhibiting the production of PGE₂, TNF-α, and IL-6 was confirmed using a mixed sample. It was confirmed that AA-2 had the best inhibitory activity on producing PGE2, TNF-α, and IL-6 rather than AA-1, AA-3, AA-4, and AA-5. For this reason, experiments were conducted using AA-2 to determine the protein expression levels of iNOS and COX-2, which are inflammation-related proteins. It was confirmed that AA-2 inhibited iNOS and COX-2 protein expression by 25.01% and 27.27%, respectively, compared to the LPS-alone treatment group. In conclusion, the mixed sample of acemannan and aloesin is judged to have anti-inflammatory activity and can potentially to be used as a functional material.

• Nuclear Engineering and Technology
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• v.56 no.4
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• pp.1501-1512
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• 2024

Plasma disruption in tokamak experiments is a challenging issue that causes damage to the device. Reliable prediction methods are needed, but the lack of full understanding of plasma disruption limits the effectiveness of physics-driven methods. Data-driven methods based on supervised learning are commonly used, and they rely on labelled training data. However, manual labelling of disruption precursors is a time-consuming and challenging task, as some precursors are difficult to accurately identify. The mainstream labelling methods assume that the precursor onset occurs at a fixed time before disruption, which leads to mislabeled samples and suboptimal prediction performance. In this paper, we present disruption prediction methods based on anomaly detection to address these issues, demonstrating good prediction performance on J-TEXT and EAST. By evaluating precursor onset times using different anomaly detection algorithms, it is found that labelling methods can be improved since the onset times of different shots are not necessarily the same. The study optimizes precursor labelling using the onset times inferred by the anomaly detection predictor and test the optimized labels on supervised learning disruption predictors. The results on J-TEXT and EAST show that the models trained on the optimized labels outperform those trained on fixed onset time labels.